先化简后求值(xy-x^2)÷(x^2-2xy+y^2)/(xy)*(x-y)/(x^2) x=-2005 y=-2

问题描述:

先化简后求值(xy-x^2)÷(x^2-2xy+y^2)/(xy)*(x-y)/(x^2) x=-2005 y=-2